I love these little Chinese chargers, I have been using them for 8 years or so, you can use one to charge both at the same time or two to charge the batteries individually, no need to isolate them to use two chargers.
And you can leave them on indefinitely as they turn themselves on and off automatically.
Charging lithium batteries is prohibited. Battery Type: All SLA batteries (Wet, MF, GEL, VRLA and Flooded), AGM (EFB). Charging current: 4~ 8A. The positive and negative electrodes must be clamped onto the battery or battery before selecting the mode to be effective.
www.ebay.com